The intermittent odd numbered Tiers are rarely if ever used for more than a passing phase. The rapid advances and constant replacement of items doesn't add a proper sense of progress to character advancement. Items have more of a meaning if they are kept for longer periods of time.
[CODE]New Item Rank Old Item Rank
The even numbered Tiers in the current system could be maintained by dumping the odd Tier items and renaming the even Tier.